Phylogenetic and antibiotic resistance analysis of Escherichia coli isolates from septicemia patients

Abstract

Escherichia coli is a major bacterium impacting human health, widely present in the environment and the human body. Its persistence challenges the immune system and facilitates opportunistic infections across all age groups. A critical strategy of E. coli is EMDR, which exacerbates chronic diseases and complicates treatment, contributing to the global crisis of antibiotic-resistant epidemics. This study investigated bacteremia caused by E. coli. A total of 100 blood samples were collected from patients exhibiting clinical symptoms such as fever, chills, and weakness. Samples were cultured anaerobically at 37°C for 24–72 hours, then subcultured on selective media. Identification use Vitek ID system, antibiotic sensitivity testing with the Vitek AST card, and 16S rRNA sequencing. Phylogenetic analysis revealed evolutionary relationships between E. coli isolates and members of the Enterobacteriaceae family. Results: showed that 75 isolates (75%) were identified as E. coli, confirming its significant role in bloodstream infections (BSI). The evolutionary tree highlighted close genetic links with resistant Enterobacteriaceae strains. To explore alternative therapies, the antibacterial activity of green tea extracts was assessed using agar well diffusion. The aqueous extract exhibited dose-dependent inhibition zones of 25, 20, 15, and 10 mm at concentrations of 40, 30, 20, and 10 mg/mL, respectively. Ethanol extracts showed stronger activity, with inhibition zones of 35, 30, 25, and 22 mm at the same concentrations.